Don't use a bona fide CustomEvent object when faking a keydown to TinyMCE. Because it takes the liberty of trying to re-write the .type property, and this will cause an exception on a real CustomEvent object because the property is declared as readonly.
Don't use a bona fide CustomEvent object when faking a keydown to TinyMCE. Because it takes the liberty of trying to re-write the .type property, and this will cause an exception on a real CustomEvent object because the property is declared as readonly.

danielpunkass/tinymce,danielpunkass/tinymce,danielpunkass/tinymce